Bulb



FIG. 1 is a top plan view of the design, the portion in shadow lines not forming a part of the design.

FIG. 2 is a side elevation view of thereof, the portion in shadow lines not forming a part of the design.

FIG. 3 is a bottom plan view thereof.

FIG. 4 is a side elevation view of a second embodiment thereof, the portion in shadow lines not forming a part of the design.

FIG. 5 is a top plan view of the second embodiment thereof; and,

FIG. 6 is a side perspective view of the third embodiment thereof, the portion in shadow lines not forming a part of the design. 

The ornamental design for a bulb, as shown and described. 